These should maximise our output from the panels and having 2 will give us some redundancy. It was also cheaper to buy two of the smaller controllers than one that was big enough for all 4 panels.

Wiring:

The panels are wired as 2 sets of panels. Each set wired in parallel to two charge controllers. Wiring in parallel although theoretically slightly less efficient should minimise any effects of shading on a single panel.

All the connections have been done with MC4 waterproof connectors. These were easy to use and means that it is straight forward if we need to change the way the panels are connected.

Each panel has 4mm2 cable running from it. Each pair of panels has 6mm2 to the MPPT controllers and connected directly to our house battery bank.